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Diffstat (limited to 'src/fdmdv_internal.h')
| -rw-r--r-- | src/fdmdv_internal.h | 197 |
1 files changed, 197 insertions, 0 deletions
diff --git a/src/fdmdv_internal.h b/src/fdmdv_internal.h new file mode 100644 index 0000000..aa9d683 --- /dev/null +++ b/src/fdmdv_internal.h @@ -0,0 +1,197 @@ +/*---------------------------------------------------------------------------*\ + + FILE........: fdmdv_internal.h + AUTHOR......: David Rowe + DATE CREATED: April 16 2012 + + Header file for FDMDV internal functions, exposed via this header + file for testing. + +\*---------------------------------------------------------------------------*/ + +/* + Copyright (C) 2012 David Rowe + + All rights reserved. + + This program is free software; you can redistribute it and/or modify + it under the terms of the GNU Lesser General Public License version 2.1, as + published by the Free Software Foundation. This program is + distributed in the hope that it will be useful, but WITHOUT ANY + WARRANTY; without even the implied warranty of MERCHANTABILITY or + FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public + License for more details. + + You should have received a copy of the GNU Lesser General Public License + along with this program; if not, see <http://www.gnu.org/licenses/>. +*/ + +#ifndef __FDMDV_INTERNAL__ +#define __FDMDV_INTERNAL__ + +#include "comp.h" +#include "codec2_fdmdv.h" +#include "codec2_fft.h" + +/*---------------------------------------------------------------------------*\ + + DEFINES + +\*---------------------------------------------------------------------------*/ + +#ifndef PI +#define PI 3.141592654 +#endif +#define FS 8000 /* sample rate in Hz */ +#define FS_VOICE_8K 8000 /* speech sample rate, 8000 Hz */ +#define FS_VOICE_16K 16000 /* speech sample rate, 16000 Hz */ +#define T (1.0/FS) /* sample period in seconds */ +#define RS 50 /* symbol rate in Hz */ +#define NC 20 /* max number of data carriers (plus one pilot in the centre) */ +#define NB 2 /* Bits/symbol for QPSK modulation */ +#define RB (NC*RS*NB) /* bit rate */ +#define M_FAC (FS/RS) /* oversampling factor */ +#define NSYM 6 /* number of symbols to filter over */ +#define NFILTER (NSYM*M_FAC) /* size of tx/rx filters at sample rate M */ + +#define FSEP 75 /* Default separation between carriers (Hz) */ + +#define NT 5 /* number of symbols we estimate timing over */ +#define P 4 /* oversample factor used for initial rx symbol filtering output */ +#define Q (M_FAC/4) /* oversample factor used for initial rx symbol filtering input */ +#define NRXDEC 31 /* number of taps in the rx decimation filter */ + +#define NPILOT_LUT (4*M_FAC) /* number of pilot look up table samples */ +#define NPILOTCOEFF 30 /* number of FIR filter coeffs in LP filter */ +#define NPILOTBASEBAND (NPILOTCOEFF+M_FAC+M_FAC/P) /* number of pilot baseband samples reqd for pilot LPF */ +#define NPILOTLPF (4*M_FAC) /* number of samples we DFT pilot over, pilot est window */ +#define MPILOTFFT 256 + +#define NSYNC_MEM 6 + +#define NRX_FDM_MEM (NFILTER+M_FAC+M_FAC/P) /* size of rx filter memory */ +#define NRXDECMEM (NRXDEC+M_FAC+M_FAC/P) /* size of rx decimation filter memory */ + +/* averaging filter coeffs */ + +#define TRACK_COEFF 0.5 +#define SNR_COEFF 0.9 /* SNR est averaging filter coeff */ + +/*---------------------------------------------------------------------------*\ + + STRUCT for States + +\*---------------------------------------------------------------------------*/ + +struct FDMDV { + + int Nc; + float fsep; + + /* test data (test frame) states */ + + int ntest_bits; + int current_test_bit; + int *rx_test_bits_mem; + + /* Modulator */ + + int old_qpsk_mapping; + int tx_pilot_bit; + COMP prev_tx_symbols[NC+1]; + COMP tx_filter_memory[NC+1][NSYM]; + COMP phase_tx[NC+1]; + COMP freq[NC+1]; + float freq_pol[NC+1]; + + /* Pilot generation at demodulator */ + + COMP pilot_lut[NPILOT_LUT]; + int pilot_lut_index; + int prev_pilot_lut_index; + + /* freq offset estimation states */ + + codec2_fft_cfg fft_pilot_cfg; + COMP pilot_baseband1[NPILOTBASEBAND]; + COMP pilot_baseband2[NPILOTBASEBAND]; + COMP pilot_lpf1[NPILOTLPF]; + COMP pilot_lpf2[NPILOTLPF]; + COMP S1[MPILOTFFT]; + COMP S2[MPILOTFFT]; + + /* baseband to low IF carrier states */ + + COMP fbb_rect; + float fbb_pol; + COMP fbb_phase_tx; + COMP fbb_phase_rx; + + /* freq offset correction states */ + + float foff; + COMP foff_phase_rect; + float foff_filt; + + /* Demodulator */ + + COMP rxdec_lpf_mem[NRXDECMEM]; + COMP rx_fdm_mem[NRX_FDM_MEM]; + COMP phase_rx[NC+1]; + COMP rx_filter_mem_timing[NC+1][NT*P]; + float rx_timing; + COMP phase_difference[NC+1]; + COMP prev_rx_symbols[NC+1]; + + /* sync state machine */ + + int sync_mem[NSYNC_MEM]; + int fest_state; + int sync; + int timer; + + /* SNR estimation states */ + + float sig_est[NC+1]; + float noise_est[NC+1]; + + /* channel simulation */ + + float sig_pwr_av; +}; + +/*---------------------------------------------------------------------------*\ + + FUNCTION PROTOTYPES + +\*---------------------------------------------------------------------------*/ + +void bits_to_dqpsk_symbols(COMP tx_symbols[], int Nc, COMP prev_tx_symbols[], int tx_bits[], int *pilot_bit, int old_qpsk_mapping); +void tx_filter(COMP tx_baseband[NC+1][M_FAC], int Nc, COMP tx_symbols[], COMP tx_filter_memory[NC+1][NSYM]); +void fdm_upconvert(COMP tx_fdm[], int Nc, COMP tx_baseband[NC+1][M_FAC], COMP phase_tx[], COMP freq_tx[], + COMP *fbb_phase, COMP fbb_rect); +void tx_filter_and_upconvert(COMP tx_fdm[], int Nc, COMP tx_symbols[], + COMP tx_filter_memory[NC+1][NSYM], + COMP phase_tx[], COMP freq[], COMP *fbb_phase, COMP fbb_rect); +void generate_pilot_fdm(COMP *pilot_fdm, int *bit, float *symbol, float *filter_mem, COMP *phase, COMP *freq); +void generate_pilot_lut(COMP pilot_lut[], COMP *pilot_freq); +float rx_est_freq_offset(struct FDMDV *f, COMP rx_fdm[], int nin, int do_fft); +void lpf_peak_pick(float *foff, float *max, COMP pilot_baseband[], COMP pilot_lpf[], codec2_fft_cfg fft_pilot_cfg, COMP S[], int nin, int do_fft); +void fdm_downconvert(COMP rx_baseband[NC+1][M_FAC+M_FAC/P], int Nc, COMP rx_fdm[], COMP phase_rx[], COMP freq[], int nin); +void rxdec_filter(COMP rx_fdm_filter[], COMP rx_fdm[], COMP rxdec_lpf_mem[], int nin); +void rx_filter(COMP rx_filt[][P+1], int Nc, COMP rx_baseband[][M_FAC+M_FAC/P], COMP rx_filter_memory[][NFILTER], int nin); +void down_convert_and_rx_filter(COMP rx_filt[NC+1][P+1], int Nc, COMP rx_fdm[], + COMP rx_fdm_mem[], COMP phase_rx[], COMP freq[], + float freq_pol[], int nin, int dec_rate); +float rx_est_timing(COMP rx_symbols[], int Nc, + COMP rx_filt[][P+1], + COMP rx_filter_mem_timing[][NT*P], + float env[], + int nin, + int m); +float qpsk_to_bits(int rx_bits[], int *sync_bit, int Nc, COMP phase_difference[], COMP prev_rx_symbols[], COMP rx_symbols[], int old_qpsk_mapping); +void snr_update(float sig_est[], float noise_est[], int Nc, COMP phase_difference[]); +int freq_state(int *reliable_sync_bit, int sync_bit, int *state, int *timer, int *sync_mem); +float calc_snr(int Nc, float sig_est[], float noise_est[]); + +#endif |